JP6764019B2 - Tape feeder - Google Patents

Description

This specification discloses a technique relating to a tape feeder having a function of stabilizing the posture of a component in a component accommodating recess of a component supply tape and sending the component to a component suction position.

Generally, the tape feeder sets a tape reel around which a component supply tape is wound, and pitch-feeds the component supply tape drawn from the tape reel by a tape feed mechanism, and the component supply tape is fed before the component suction position. The cover tape (also called cover film, top tape, or top film) is peeled off from the upper surface, and the parts in the parts accommodating recess of the parts supply tape are sucked by the suction nozzle of the parts mounting machine at the parts suction position. ing.

Further, in the tape feeder described in Patent Document 1 (Japanese Unexamined Patent Publication No. 11-307992), a permanent magnet that magnetically attracts a component in a component accommodating recess of a component supply tape is installed below a component suction position. The magnetic attraction force prevents the component from popping out from the component accommodating recess and the component from rising when the component is attracted.

Further, the tape feeder described in Patent Document 2 (Japanese Patent No. 4809506) has an L-shape over a region from a position three minutes before the component accommodating recess to the component adsorption position. A permanent magnet having a shape is provided, and a vibrator that vibrates the component supply tape in the width direction is provided. By the vibration, the component in the component accommodating recess is moved to one side of the component accommodating recess to be positioned and attracted by the magnetic force of the permanent magnet. I try to hold it. In this case, the permanent magnet that attracts the parts is formed in an L shape so as to act a magnetic force in the direction of moving the parts in the parts accommodating recess toward one side of the component accommodating recesses.

Japanese Unexamined Patent Publication No. 11-307992 Japanese Patent No. 4809506

As shown in FIG. 5, in the component supply tape 13, since the upper edge of the component accommodating recess 22 is formed in an R shape, a gap is formed between the upper edge of the component accommodating recess 22 and the cover tape 23. Therefore, when the parts in the component accommodating recess 22 are thin parts, even if the upper surface of the component accommodating recess 22 is covered with the cover tape 23, a piece of the component in the component accommodating recess 22 The edge may ride on the upper edge of the component accommodating recess 22, or as shown in FIG. 6, both diagonal portions of the component may ride on the upper edge of the component accommodating recess 22. Such a state is generated by vibration during the pitch feed operation of the component supply tape 13 (during the operation of the component mounting machine), and during transportation or replacement work of the tape reel 14 on which the component supply tape 13 is wound. Can also occur. Further, there is a possibility that the parts in the component accommodating recess 22 may ride on the upper edge of the component accommodating recess 22 due to vibration or static electricity when the cover tape 23 is peeled off before the component suction position.

However, in Patent Document 1, since the part in the component accommodating recess that has reached the component attraction position is only attracted by the permanent magnet from below, the component in the component accommodating recess rides on the upper edge of the component accommodating recess. Even if it is in a state of being stuck, the effect of eliminating the riding state is small.

On the other hand, in Patent Document 2, since the component supply tape is provided with an oscillator that vibrates in the width direction and a drive source thereof, not only the configuration is complicated and the cost is high, but also the component supply tape is laterally provided. It is necessary to secure a space for installing the oscillator, and there is a drawback that the width dimension of the tape feeder becomes large. Moreover, since the position where the oscillator is installed is near the component suction position and there is a tape feeding mechanism such as a sprocket that pitch-feeds the component supply tape below the component suction position, it is near the component suction position. With a tape feeder that has a small amount of free space and has become thinner in recent years, it is difficult in terms of space to install an oscillator and its drive source near the component suction position.

In order to solve the above problems, a tape reel in which a parts supply tape wound by accommodating and packaging parts in a part accommodating recess formed at a predetermined pitch is set in a feeder main body and pulled out from the tape reel. The supply tape is pitch-fed by the tape feed mechanism, the cover tape is peeled off from the upper surface of the component supply tape before the component suction position, and the component in the component accommodating recess of the component supply tape is componentized at the component suction position. In the tape feeder sucked by the suction nozzle of the mounting machine, the component accommodating recess protruding toward the lower surface side of the component supply tape in the middle of the path of sending the component supply tape pulled out from the tape reel to the peeling position of the cover tape. It is provided with a protrusion provided so as to interfere with each other and a component suction magnet provided on the bottom surface of a tape passage for feeding a component supply tape that has passed over the protrusion to the component suction position, and pitch feed of the tape feed mechanism. When the component supply tape is pulled by the operation and passes over the protrusion, the component accommodating recess protruding toward the lower surface side of the component supply tape vibrates the component supply tape by overcoming the protrusion. The parts riding on the upper edge of the component accommodating recess are shaken off to the bottom surface of the component accommodating recess, and the parts in the component accommodating recess are attracted and held on the bottom surface by the magnetic force of the component suction magnet and sent to the component suction position. It is configured in.

In this configuration, the component supply tape is vibrated by causing the component storage recess protruding toward the lower surface side of the component supply tape to interfere with the protrusion while applying tension to the component supply tape by the pitch feed operation of the tape feed mechanism. Therefore, the component supply tape can be vibrated only by providing the tape feeder with a protrusion that interferes with the component accommodating recess of the component supply tape, and the configuration is extremely simple. Moreover, the position where the protrusion is provided may be anywhere in the middle of the path of sending the component supply tape pulled out from the tape reel to the peeling position of the cover tape, so select a position where there is enough space to provide the protrusion. It can be provided, and it is easy to put it into practical use, and it is possible to avoid increasing the width dimension of the tape feeder. Furthermore, since a component suction magnet is provided on the bottom surface of the tape passage that sends the component supply tape that has passed over the protrusion to the component suction position, the component supply tape that has passed over the protrusion passes through the tape passage to the component suction position. Even if the parts supply tape vibrates in the process, the parts in the parts storage recess of the parts supply tape are attracted to the bottom surface of the parts storage recess by the magnetic force of the parts suction magnet and sent to the component suction position in a stable posture. be able to. Since the cover tape of the component supply tape passing through the tape passage is peeled off before the component suction position, vibration and static electricity are generated when the cover tape is peeled off, but the component accommodating recess is also generated at the cover tape peeling position. Since the parts inside are attracted and held on the bottom surface of the component accommodating recess by the magnetic force of the component attraction magnet, the components inside the component accommodating recess are attracted and held by the vibration and static electricity generated when the cover tape is peeled off. It is possible to prevent the parts from riding on the upper edge, and the parts in the parts accommodating recess can be sent to the parts suction position in a stable posture.

In this case, it is preferable to provide a tape holding member for suppressing the lifting of the component supply tape that has passed over the protrusion at least in the portion of the tape passage closer to the protrusion. If the lift of the component supply tape that has passed over the protrusion is pressed by the tape holding member, the component storage recess of the component supply tape can be more reliably interfered with the protrusion, and the component supply from the component suction magnet can be performed. The lifting of the tape can also be suppressed.

Here, the tape holding member may be formed of a non-magnetic material (for example, a non-magnetic metal such as plastic, aluminum, or copper). If the tape holding member is made of a magnetic material such as iron, the tape holding member may become magnetic due to the influence of the magnet of the component attracting magnet as the period of use becomes longer, and the effect of stabilizing the component posture by the component attracting magnet may decrease. Because there is.

Further, at least a portion of the component suction magnet located below the tape pressing member is configured to be vertically displaceable, and the portion is pushed up or pulled up by an elastic member to be placed between the component and the tape pressing member. The supply tape may be sandwiched. In this way, the elastic member ensures that the component suction magnet is brought into contact with the lower surface of the component storage recess of the component supply tape, and the component in the component storage recess can be reliably attracted and held by the magnetic force of the component suction magnet.

Alternatively, the tape pressing member may be supported so as to be vertically displaceable, and the tape pressing member may be pushed down or pulled down by the elastic member to sandwich the component supply tape between the tape pressing member and the component suction magnet. Even in this way, the lower surface of the component accommodating recess of the component supply tape can be reliably brought into contact with the component suction magnet by the elastic member, and the component in the component accommodating recess can be reliably attracted and held by the magnetic force of the component attraction magnet.

The component suction magnet may be configured by arranging a plurality of magnets in a row on the bottom surface of the tape passage, but in this configuration, the magnetic force fluctuates at the joint of the plurality of magnets, and the component in the component accommodating recess is formed. Since the posture of the parts may become unstable, the component suction magnet may be composed of one magnet sheet or magnet plate formed in a tape shape.

Further, it is desirable that the component suction magnet is magnetized so that the magnetizing region of the north pole and the magnetizing region of the south pole extend in the feeding direction of the component supply tape. In this way, uniform magnetism can be continuously applied from the component suction magnet to the component in the component storage recess that is sent to the component suction position on the component suction magnet provided on the bottom surface of the tape passage. It is possible to send the parts in the parts accommodating recess to the parts suction position in a more stable posture.

Further, the protrusions may be configured to be adjustable in height or replaceable with those having different heights. For example, by adjusting the height of the protrusion, the amount of interference between the protrusion and the component accommodating recess can be adjusted to adjust the strength of vibration applied to the component supply tape. In addition, since the height of the component accommodating recess changes depending on the type of component supply tape used, if the height of the protrusion is adjusted according to the height of the component accommodating recess, the height of the component accommodating recess is different. With respect to the supply tape, the amount of interference between the component accommodating recess and the protrusion (the strength of vibration applied to the component supply tape) can be appropriately adjusted.

FIG. 1 is a perspective view of a tape feeder of one embodiment. FIG. 2 is a partially enlarged view illustrating a function of applying vibration to the component supply tape. FIG. 3 is an enlarged perspective view showing the function of applying vibration to the component supply tape by breaking along the lines III-III of FIG. FIG. 4 is an enlarged cross-sectional view showing a configuration in which a component suction magnet is pushed up and a component supply tape is sandwiched between the component suction magnet and the tape holding member by breaking along the lines IV-IV of FIG. FIG. 5 is a partially enlarged cross-sectional view of the component supply tape showing a state in which one edge of the component in the component accommodating recess of the component supply tape rides on the upper edge of the component accommodating recess. FIG. 6 is a partially enlarged plan view of the component supply tape showing a state in which the corners of the component in the component accommodating recess of the component supply tape in four directions ride on the upper edge of the component accommodating recess. FIG. 7 is a partially enlarged plan view showing the magnetizing pattern of the component suction magnet.

An embodiment will be described below.

First, the configuration of the tape feeder will be described with reference to FIG.

A tape reel 14 on which an embossed component supply tape 13 is wound can be detachably set on the handle portion 12 side of the feeder main body 11 of the tape feeder. A tape passage 15 for sending the component supply tape 13 drawn from the tape reel 14 to the component suction position is provided on the upper surface of the feeder main body 11. A tape feeding mechanism (not shown) for pitch-feeding the component supply tape 13 set in the tape passage 15 to the component suction position is provided on the back side (opposite side of the handle portion 12) of the feeder main body 11. .. A communication connector 16 connected to a connector (not shown) on the component mounting machine side and positioning pins 17 and 18 for determining a mounting position with respect to the component mounting machine are provided on the back end surface of the feeder main body 11.

In general, as shown in FIGS. 5 and 6, the component supply tape 13 accommodates one component in each component accommodating recess 22 embossed in a row on a resin carrier tape 21 at a constant pitch, and the carrier. By attaching the cover tape 23 to the upper surface of the tape 21 so as to be peelable, the upper surface opening of each component accommodating recess 22 is closed by the cover tape 23. As shown in FIG. 6, at the side edge of the carrier tape 21 of the component supply tape 13, feed holes 24 are formed in a row at a constant pitch with each component accommodating recess 22 in a constant positional relationship, and the feed holes 24 are formed. By engaging the teeth of the sprocket (not shown) of the tape feeding mechanism and intermittently rotating the sprocket by a predetermined angle with a motor (not shown) such as a stepping motor, the component supply tape 13 is moved to the component suction position. Pitch feed. Although not shown, the sprocket is arranged below the component suction position, and the cover tape 23 is peeled off from the upper surface of the component supply tape 13 before the component suction position to expose the components in the component accommodating recess 22. become.

A vibration applying unit 31 that applies vibration to the component supply tape 13 is attached to the feeder body 11 with screws 32 or the like in the middle of the path of sending the component supply tape 13 pulled out from the tape reel 14 to the peeling position of the cover tape 23. There is. As shown in FIGS. 2 and 3, the vibration applying unit 31 is provided with a protrusion 33 so as to interfere with a component accommodating recess 22 projecting toward the lower surface side of the component supply tape 13. The protrusion 33 is formed of a metal plate, a leaf spring, or the like, and is replaceably attached to the base member 35 of the vibration applying unit 31 with a screw 34 or the like. For example, by replacing the protrusion 33 with one having a different height, the amount of interference between the protrusion 33 and the component accommodating recess 22 can be adjusted to adjust the strength of vibration applied to the component supply tape 13. it can. Further, since the height of the component accommodating recess 22 changes depending on the type of the component supply tape 13 used, if the protrusion 33 is replaced with one having a height corresponding to the height of the component accommodating recess 22, the component accommodating recess 22 can be replaced. The amount of interference between the component accommodating recess and the protrusion 33 (the strength of vibration applied to the component supply tape 13) can be appropriately adjusted even for the component supply tapes 13 having different heights. The protrusion 33 may be provided on the base member 35 of the vibration applying unit 31 so that the height can be adjusted.

Further, a tape pressing member 36 for suppressing the lifting of the component supply tape 13 that has passed over the protrusion 33 is attached to the base member 35 of the vibration applying unit 31 with screws 37 or the like. The tape holding member 36 is made of a non-magnetic material (for example, a non-magnetic metal such as plastic, aluminum, or copper) so as not to be magnetic.

A component suction magnet 41 is provided on the bottom surface of the tape passage 15 that sends the component supply tape 13 that has passed over the protrusion 33 to the component suction position, and the component of the component supply tape 13 is provided by the magnetic force of the component suction magnet 41. It is configured to suck and hold the parts in the accommodating recess 22 on the bottom surface thereof and send them to the component suction position. The component suction magnet 41 extends from a position on the lower side of the tape holding member 36 near the protrusion 33 to a position slightly beyond the component suction position.

In this case, the component suction magnet 41 may be configured by arranging a plurality of magnets in a row on the bottom surface of the tape passage 15, but in this configuration, the magnetic force fluctuates at the joint of the plurality of magnets to accommodate the component. The posture of the parts in the recess 22 may become unstable. Therefore, in this embodiment, the component suction magnet 41 is composed of one magnet sheet or magnet plate formed in a tape shape.

Further, as shown in FIG. 7, the component suction magnet 41 is magnetized so that the magnetizing region of the N pole and the magnetizing region of the S pole extend in the feeding direction of the component supply tape 13, and the component on the bottom surface of the tape passage 15 The parts in the component accommodating recess 22 that moves on the suction magnet 41 are sent to the component suction position while maintaining the state of straddling the north and south poles of the component suction magnet 41. In this way, uniform magnetism can be continuously applied from the component suction magnet 41 to the component in the component storage recess 22 sent to the component suction position on the component suction magnet 41 on the bottom surface of the tape passage 15. It is possible to send the parts in the parts accommodating recess 22 to the parts suction position in a more stable posture.

Further, at least a portion of the component suction magnet 41 located below the tape holding member 36 is formed so as to be vertically displaceable, and as shown in FIGS. 3 and 4, of the base member 35 of the vibration applying unit 31. An elastic member 42 such as a spring or rubber that pushes up the component suction magnet 41 is provided at a position corresponding to the lower side of the tape holding member 36, and the elastic member 42 pushes up the component suction magnet 41 to form the component suction magnet 41. The component supply tape 13 is sandwiched between the tape holding member 36 and the tape holding member 36. As a result, the elastic member 42 ensures that the component suction magnet 41 is brought into contact with the lower surface of the component storage recess 22 of the component supply tape 13, and the component inside the component storage recess 22 can be reliably attracted and held by the magnetic force of the component suction magnet 41. I am doing it.

When the component supply tape 13 pulled out from the tape reel 14 is set in the tape passage 15 at the time of replacing the tape reel 14, the operator pushes down the component suction magnet 41 with a fingertip or the like to push down the component suction magnet 41. The gap between the 41 and the tape holding member 36 is widened, and the component suction magnet 41 is inserted into the gap and set in the tape passage 15.

In this embodiment, the tape pressing member 36 is fixed to the base member 35 of the vibration applying unit 31, but the tape pressing member 36 is provided on the base member 35 of the vibration applying unit 31 so as to be openable and closable by a hinge or the like. When the component supply tape 13 is set, the tape pressing member 36 is opened, and after the component supply tape 13 is set, the tape pressing member 36 is closed and the tape pressing member 36 is held in the closed state by a clamp mechanism or the like. Is also good. Alternatively, the tape holding member 36 may be detachably attached to the base member 35 of the vibration applying unit 31 by an engaging mechanism or the like, and the tape holding member 36 may be removed when the component supply tape 13 is set.

As shown in FIG. 5, in the component supply tape 13, since the upper edge of the component accommodating recess 22 is formed in an R shape, a gap is formed between the upper edge of the component accommodating recess 22 and the cover tape 23. Therefore, when the parts in the component accommodating recess 22 are thin parts, even if the upper surface of the component accommodating recess 22 is covered with the cover tape 23, a piece of the component in the component accommodating recess 22 The edge may ride on the upper edge of the component accommodating recess 22, or as shown in FIG. 6, both diagonal portions of the component may ride on the upper edge of the component accommodating recess 22. Such a state is generated by vibration during the pitch feed operation of the component supply tape 13 (during the operation of the component mounting machine), and during transportation or replacement work of the tape reel 14 on which the component supply tape 13 is wound. Can also occur. Further, there is a possibility that the parts in the component accommodating recess 22 may ride on the upper edge of the component accommodating recess 22 due to vibration or static electricity when the cover tape 23 is peeled off before the component suction position.

Therefore, in the present embodiment, when the component supply tape 13 is pulled by the pitch feed operation of the tape feed mechanism and passes over the protrusion 33, the component accommodating recess 22 protruding toward the lower surface side of the component supply tape 13 is the same. By overcoming the protrusion 33, the component supply tape 13 is vibrated, and the component that rides on the upper edge of the component accommodating recess 22 is shaken off to the bottom surface of the component accommodating recess 22, and the component is subjected to the magnetic force of the component suction magnet 41. The parts in the accommodating recess 22 are sucked and held on the bottom surface and sent to the parts suction position.

In this configuration, the component supply tape 13 is made to interfere with the protrusion 33 by causing the component accommodating recess 22 protruding toward the lower surface side of the component supply tape 13 while applying tension to the component supply tape 13 by the pitch feed operation of the tape feed mechanism. Since the tape feeder is vibrated, the component supply tape 13 can be vibrated simply by providing the tape feeder with a protrusion 33 that interferes with the component accommodating recess 22 of the component supply tape 13, the configuration is extremely simple, and the cost is low. Can meet the demands of conversion.

Moreover, the position where the protrusion 33 is provided (the position where the vibration applying unit 31 is provided) may be anywhere as long as it is in the middle of the path of sending the component supply tape 13 pulled out from the tape reel 14 to the peeling position of the cover tape 23. The protrusion 33 (vibration imparting unit 31) can be provided at a position where there is sufficient space, which facilitates practical use and avoids an increase in the width dimension of the tape feeder.

Further, since the component suction magnet 41 is provided on the bottom surface of the tape passage 15 that sends the component supply tape 13 that has passed over the protrusion 33 to the component suction position, the component supply tape 13 that has passed over the protrusion 33 is the tape passage 15. Even if the component supply tape 13 vibrates in the process of reaching the component suction position through the component supply tape 13, the component in the component accommodating recess 22 of the component supply tape 13 is attracted to the bottom surface of the component accommodating recess 22 by the magnetic force of the component attraction magnet 41. It can be sent to the component suction position in a stable posture while holding it.

Since the cover tape 23 of the component supply tape 13 passing through the tape passage 15 is peeled off before the component suction position, vibration and static electricity are generated when the cover tape 23 is peeled off, but at the peeled position of the cover tape 23 However, since the parts in the component accommodating recess 22 are attracted and held on the bottom surface of the component accommodating recess 22 by the magnetic force of the component attraction magnet 41, the component accommodating recess 22 is caused by vibration and static electricity generated when the cover tape 23 is peeled off. It is possible to prevent the parts in the component accommodating recess 22 from riding on the upper edge of the component accommodating recess 22, and the components in the component accommodating recess 22 can be sent to the component suction position in a stable posture.

Moreover, in the present embodiment, the tape holding member 36 for suppressing the lifting of the component supply tape 13 that has passed over the protrusion 33 is provided at least in the portion of the tape passage 15 that is closer to the protrusion 33. The lifting of the component supply tape 13 that has passed over the protrusion 33 can be suppressed, the component accommodating recess 22 of the component supply tape 13 can be more reliably interfered with the protrusion 33, and the component suction magnet 41 can be used. It is also possible to suppress the lifting of the component supply tape 13.

Further, at least a portion of the component suction magnet 41 located below the tape pressing member 36 is formed so as to be vertically displaceable, and the component suction magnet 41 is pushed up by the elastic member 42 to push up the component suction magnet 41 and the tape pressing member. Since the component supply tape 13 is sandwiched between the component supply tape 13 and the component supply tape 13, the elastic member 42 ensures that the component suction magnet 41 is brought into contact with the lower surface of the component accommodating recess 22 of the component supply tape 13, and is contained in the component accommodating recess 22. The parts can be reliably attracted and held by the magnetic force of the component suction magnet 41.

In this embodiment, the elastic member 42 pushes up the component suction magnet 41, but the component suction magnet 41 may be pulled up.

Alternatively, the tape pressing member 36 may be supported so as to be vertically displaceable, and the tape pressing member 36 may be pushed down or pulled down by the elastic member to sandwich the component supply tape 13 with the component suction magnet 41. Even in this way, the lower surface of the component accommodating recess 22 of the component supply tape 13 is surely brought into contact with the component suction magnet 41 by the elastic member, and the component in the component accommodating recess 22 is reliably attracted by the magnetic force of the component suction magnet 41. Can be retained.

In addition, the present invention is not limited to the above embodiment, and various modifications are made within a range that does not deviate from the gist, such as changing the shape of the protrusion 33 or changing the configuration of the tape feeder. It goes without saying that you can do it.

11 ... Feeder body, 13 ... Parts supply tape, 14 ... Tape reel, 15 ... Tape passage, 21 ... Carrier tape, 22 ... Parts storage recess, 23 ... Cover tape, 24 ... Feed hole, 31 ... Vibration imparting unit, 33 ... Projection, 35 ... Base member, 36 ... Tape holding member, 41 ... Parts

Claims (8)

A tape reel wound with a parts supply tape in which parts are housed and packaged in a parts storage recess formed at a predetermined pitch is set in the feeder body, and the parts supply tape pulled out from the tape reel is pitched by a tape feed mechanism. The cover tape is peeled off from the upper surface of the component supply tape just before the component suction position, and the component in the component accommodating recess of the component supply tape is suctioned by the suction nozzle of the component mounting machine at the component suction position. In the tape feeder
A protrusion provided so as to interfere with the component accommodating recess protruding on the lower surface side of the component supply tape in the middle of the path for sending the component supply tape pulled out from the tape reel to the peeling position of the cover tape.
It is provided with a component suction magnet provided on the bottom surface of the tape passage that sends the component supply tape that has passed over the protrusion to the component suction position.
When the component supply tape is pulled by the pitch feed operation of the tape feed mechanism and passes over the protrusion, the component accommodating recess protruding toward the lower surface side of the component supply tape gets over the protrusion, thereby causing the component. The supply tape is vibrated to shake off the part riding on the upper edge of the part accommodating recess to the bottom surface of the component accommodating recess, and the magnetic force of the component suction magnet attracts and holds the component in the component accommodating recess to the bottom surface. A tape feeder configured to feed to the component suction position. The tape feeder according to claim 1, wherein a tape pressing member for suppressing the lifting of the component supply tape that has passed over the protrusion is provided at least in a portion of the tape passage closer to the protrusion. The tape feeder according to claim 2, wherein the tape holding member is made of a non-magnetic material. At least a portion of the component suction magnet located below the tape pressing member is configured to be vertically displaceable, and the elastic that pushes up or pulls up the portion to sandwich the component supply tape with the tape pressing member. The tape feeder according to claim 2 or 3, wherein the member is provided. The tape holding member is supported so as to be vertically displaceable, and an elastic member for pushing down or pulling down the tape holding member and sandwiching the component supply tape between the tape holding member and the component suction magnet is provided, according to claim 2 or 3. The tape feeder described. The tape feeder according to any one of claims 1 to 5, wherein the component suction magnet is composed of a single magnet sheet or a magnet plate formed in a tape shape. The tape feeder according to claim 6, wherein the component suction magnet is magnetized so that the magnetizing region of the north pole and the magnetizing region of the south pole extend in the feeding direction of the component supply tape. The tape feeder according to any one of claims 1 to 7, wherein the protrusion is configured to be adjustable in height or replaceable with a different height.

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